Researchers at NOAA’s Earth System Research Lab (ESRL) Global Monitoring Division (GMD) conduct continuous measurements of atmospheric composition at Summit Station to better understand changes occurring in the Arctic and Earth system. Continuous measurements include: 1. Halocarbon and other Atmospheric Trace Gases (HATS) Flasks: weekly to biweekly air sampling collection to measure trace gases that are important components of global halocarbon chemistry. These measurements have been ongoing since 2004. 2. Carbon Cycle Greenhouse Gas (CCGG) Flasks: weekly air sampling experiment to analyze levels of trace gases that are part of the global carbon cycle. These measurements were taken during winter of 1997-1998, 2000-2001, 2001-2002, and have been on-going since the 2003-2004 winter period. 3. In-situ Aerosol Sampling Suite: continual measurements of aerosol optical properties to determine aerosol radiative effects. These measurements were initiated in 2003 with an updated suite of instruments in 2009. 4. Surface ozone measurements: continual tropospheric air sampling efforts for ozone levels. These measurements were taken from 2000 to 2002, and from 2003 on. 5. Balloon-borne ozonesondes: measurements of year-round ozone atmospheric profiles. These measurements were first conducted during the late-winter of 2005. 6. In-situ Monitoring with the Chromatograph for Atmospheric Trace Species (CATS): a three-channel gas chromatograph performs hourly measurements of ozone depleting gases identified in the Montreal Protocol and amendments including nitrous oxide, sulfur hexafluoride, CFC-12, CFC-11, CFC-113, chloroform, methyl chloroform, and carbon tetrachloride. These measurements began in 2007. 7. Surface Meteorology: continuous measurements of surface meteorological properties to support both science and flight operations. These measurements have been continuous since summer 2005. 8. Surface Solar Radiation: continuous measurements of broadband solar and thermal radiation. These measurements began in 2013 with additional instruments added in 2016.

Logistics Summary

For this NOAA program, on-site science technicians maintain a suite of year-round measurements on behalf of NOAA researchers. These measurements began in the mid 1990s and are ongoing (part of GEOSummit since 2003). NOAA representatives visit Summit Station annually to install / maintain instruments, train science technicians, and conduct measurements. Starting in 2005, NOAA began staffing science technician rotations as Summit Station during the winter phases. Beginning in 2008 NOAA increased staffing to be year-round. Monitoring projects on site include: carbon cycle gas sampling flasks, black carbon measurement, halocarbons and trace species flask sampling, meteorology suite, stratospheric ozonesondes, aerosol measurements, surface ozone measurements, and an in-situ gas chromatograph for greenhouse gas measurements. NOAA will continue to collaborate with Georgia Tech on activities related to the aerosol instrument suite that was previously installed and maintained by the Bergin project (NSF grant #1023227). NOAA program highlights at Summit Station over the last few years include: - During summer 2007 a four channel gas chromatograph was added to the suite of NOAA instruments. - During summer 2008, in addition to ongoing work, researchers extended the ozonesonde experiment by launching about 20 additional balloons in April and again in July for an intensive field campaign. - In February 2009, a NOAA staff member flew to Summit Station via the Twin Otter on a crew turnover flight to repair an instrument, departing the station on the return flight approximately one week later. - During August 2009, the NOAA field coordinator attended an on-site planning meeting. - In 2010, in addition to ongoing measurements, CPS staff relocated the Temporary Atmospheric Watch Observatory (TAWO) and instrument tower (where the NOAA instruments are mounted) to approximately 1 km south of Summit Station. - During 2011 and 2012 the NOAA field coordinator made a routine visit to Summit Station for instrument maintenance. - During 2013 the TAWO building was lifted and the TAWO tower was extended. The on-site science technicians coordinated with the Boulder-based NOAA team to support the instrumentation during the transition. - Also during 2013, the NOAA ESRL GMD deputy director traveled to Summit Station in late June for a site visit. During 2014, one NOAA researcher will travel to Summit in June for maintenance and upgrade activities. NOAA will continue to hire and deploy science technicians for all the three staffing phases. During 2015, three researchers will travel to Summit in June, July, and August for maintenance and upgrade activities. These include upgrading the meteorological sensor suite, assisting with the science impacts from the TAWO facility raise project, and performing a quality control visit to evaluate the setup of the aerosol measuring suite of instrumentation. In 2016, NOAA researchers will travel to Summit to relocate the meteorological suite of instruments from the TAWO tower to the 50m tower, install broadband solar radiometers to inter-compare with existing solar measurements from Summit station, reinstall instrument inlets on the TAWO inlet mast, and potentially reconfigure the TAWO interior layout of instruments to optimize the available footprint. Additionally, NOAA is planning to modify the CATS GC to eliminate methane containing P5 carrier gas to directly address concerns about elevated methane levels within the facility. In 2017 a field team of two will demobilize a portion of the NOAA project activities including the ozonesonde system and materials, the CATS GC, and the solar radiation suite (contingent on the timing of calibrated radiometers being returned by the Steffen/NASAAWS project). The field team will also recover components of the meteorological suite from the failed 50m tower and re-install met instruments on the TAWO tower which was relocated 80m south TAWO during June 2017. The science technician position provided via inter-agency transfer will be ended on or about 28 August 2017. Researchers may return in 2018, details are TBD.

CPS will coordinate personnel and cargo transport to and from Summit, provide access to Summit Station infrastructure, Summit user days, Kangerlussuaq user days, and science technician support with tasking shared between the NOAA and CPS year-round technicians. The PI will arrange and pay for all other logistics through the grant.

This site is administered by the Science Coordination Office for Summit Station and the Greenland Traverse (University of New Hampshire, University of California - Merced, and Dartmouth). This material is based on work supported by the National Science Foundation under awards OPP-1637006 to the University of New Hampshire, OPP-1637209 to the University of California - Merced, and OPP-1637003 to Dartmouth College. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.